Currently, the electronics industry sees a rapid progress of semiconductor devices. Integration of the elements is improved as the dimensions of the semiconductor devices are reduced. Accordingly, various efforts have been made to fabricate ultrafine devices.
Conventionally, fabrication of submicron devices is implemented by downsizing the normal transistors. This downsizing is based on the lithography technology.
More specifically, a resist film, which is capable of being modified by light, X-rays, electron beams or the like, is applied to a substrate. A reticle (photomask) having an appropriate pattern is then placed thereon. Light, X-rays, electron beams or the like is radiated through the reticle in order to modify the resist film. Either the modified or unmodified resist film is then removed to form a resist pattern on the substrate.
On the other hand, the semiconductor industry shows the possibilities of a quantum effect element in a semiconductor region having a size of several tens of nanometers because of its excellent functionality. Accordingly, establishment of the processing technology for forming ultrafine structures with a size of several tens of nanometers or less has been demanded in the semiconductor industry.
However, there is a limit in the lithography technology in terms of accuracy for the following reasons: photomask alignment error cannot be eliminated; there is a limit in the technology of reducing the mask size; and a resist material is not capable of being modified in a satisfactory manner by light or the like. Accordingly, the lithography technology is problematic in forming fine structures having a size of several tens of nanometers.
Various efforts have been made to solve the above problems like using the self-alignment technology to minimize the use of the lithography process. However, even these methods do not completely solve the problems in forming the uniform, fine structures.
Problems
Accordingly, it is a prime task in the field of ultrafine semiconductor devices with a size of several tens of nanometers or less to develop a method capable of accurately processing a fine structure in a manner suitable for mass production, which is heretofore impossible. For practical applications of the semiconductor devices, the produced fine structures are required to have a uniform size.
The present invention is made to solve the above problems, and it is an object of the present invention to propose a method capable of accurately processing a fine structure in a manner suitable for mass production.